/* -*-mode:java; c-basic-offset:2; indent-tabs-mode:nil -*- */
/* JOrbis
 * Copyright (C) 2000 ymnk, JCraft,Inc.
 *  
 * Written by: 2000 ymnk<ymnk@jcraft.com>
 *   
 * Many thanks to 
 *   Monty <monty@xiph.org> and 
 *   The XIPHOPHORUS Company http://www.xiph.org/ .
 * JOrbis has been based on their awesome works, Vorbis codec.
 *   
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public License
 * as published by the Free Software Foundation; either version 2 of
 * the License, or (at your option) any later version.
   
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Library General Public License for more details.
 * 
 * You should have received a copy of the GNU Library General Public
 * License along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

package com.jcraft.jogg;

public class StreamState {
	byte[] body_data; /* bytes from packet bodies */
	int body_storage; /* storage elements allocated */
	int body_fill; /* elements stored; fill mark */
	private int body_returned; /* elements of fill returned */

	int[] lacing_vals; /* The values that will go to the segment table */
	long[] granule_vals; /*
							 * pcm_pos values for headers. Not compact this way, but it is simple coupled to the lacing fifo
							 */
	int lacing_storage;
	int lacing_fill;
	int lacing_packet;
	int lacing_returned;

	byte[] header = new byte[282]; /* working space for header encode */
	int header_fill;

	public int e_o_s; /*
						 * set when we have buffered the last packet in the logical bitstream
						 */
	int b_o_s; /*
				 * set after we've written the initial page of a logical bitstream
				 */
	int serialno;
	int pageno;
	long packetno; /*
					 * sequence number for decode; the framing knows where there's a hole in the data, but we need coupling so that the codec (which is in a seperate abstraction layer) also knows
					 * about the gap
					 */
	long granulepos;

	public StreamState() {
		init();
	}

	StreamState(int serialno) {
		this();
		init(serialno);
	}

	void init() {
		body_storage = 16 * 1024;
		body_data = new byte[body_storage];
		lacing_storage = 1024;
		lacing_vals = new int[lacing_storage];
		granule_vals = new long[lacing_storage];
	}

	public void init(int serialno) {
		if (body_data == null) {
			init();
		} else {
			for (int i = 0; i < body_data.length; i++)
				body_data[i] = 0;
			for (int i = 0; i < lacing_vals.length; i++)
				lacing_vals[i] = 0;
			for (int i = 0; i < granule_vals.length; i++)
				granule_vals[i] = 0;
		}
		this.serialno = serialno;
	}

	public void clear() {
		body_data = null;
		lacing_vals = null;
		granule_vals = null;
	}

	void destroy() {
		clear();
	}

	void body_expand(int needed) {
		if (body_storage <= body_fill + needed) {
			body_storage += (needed + 1024);
			byte[] foo = new byte[body_storage];
			System.arraycopy(body_data, 0, foo, 0, body_data.length);
			body_data = foo;
		}
	}

	void lacing_expand(int needed) {
		if (lacing_storage <= lacing_fill + needed) {
			lacing_storage += (needed + 32);
			int[] foo = new int[lacing_storage];
			System.arraycopy(lacing_vals, 0, foo, 0, lacing_vals.length);
			lacing_vals = foo;

			long[] bar = new long[lacing_storage];
			System.arraycopy(granule_vals, 0, bar, 0, granule_vals.length);
			granule_vals = bar;
		}
	}

	/* submit data to the internal buffer of the framing engine */
	public int packetin(Packet op) {
		int lacing_val = op.bytes / 255 + 1;

		if (body_returned != 0) {
			/*
			 * advance packet data according to the body_returned pointer. We had to keep it around to return a pointer into the buffer last call
			 */

			body_fill -= body_returned;
			if (body_fill != 0) {
				System.arraycopy(body_data, body_returned, body_data, 0, body_fill);
			}
			body_returned = 0;
		}

		/* make sure we have the buffer storage */
		body_expand(op.bytes);
		lacing_expand(lacing_val);

		/*
		 * Copy in the submitted packet. Yes, the copy is a waste; this is the liability of overly clean abstraction for the time being. It will actually be fairly easy to eliminate the extra copy in
		 * the future
		 */

		System.arraycopy(op.packet_base, op.packet, body_data, body_fill, op.bytes);
		body_fill += op.bytes;

		/* Store lacing vals for this packet */
		int j;
		for (j = 0; j < lacing_val - 1; j++) {
			lacing_vals[lacing_fill + j] = 255;
			granule_vals[lacing_fill + j] = granulepos;
		}
		lacing_vals[lacing_fill + j] = (op.bytes) % 255;
		granulepos = granule_vals[lacing_fill + j] = op.granulepos;

		/* flag the first segment as the beginning of the packet */
		lacing_vals[lacing_fill] |= 0x100;

		lacing_fill += lacing_val;

		/* for the sake of completeness */
		packetno++;

		if (op.e_o_s != 0)
			e_o_s = 1;
		return (0);
	}

	public int packetout(Packet op) {

		/*
		 * The last part of decode. We have the stream broken into packet segments. Now we need to group them into packets (or return the out of sync markers)
		 */

		int ptr = lacing_returned;

		if (lacing_packet <= ptr) {
			return (0);
		}

		if ((lacing_vals[ptr] & 0x400) != 0) {
			/* We lost sync here; let the app know */
			lacing_returned++;

			/*
			 * we need to tell the codec there's a gap; it might need to handle previous packet dependencies.
			 */
			packetno++;
			return (-1);
		}

		/* Gather the whole packet. We'll have no holes or a partial packet */
		{
			int size = lacing_vals[ptr] & 0xff;
			int bytes = 0;

			op.packet_base = body_data;
			op.packet = body_returned;
			op.e_o_s = lacing_vals[ptr] & 0x200; /* last packet of the stream? */
			op.b_o_s = lacing_vals[ptr] & 0x100; /* first packet of the stream? */
			bytes += size;

			while (size == 255) {
				int val = lacing_vals[++ptr];
				size = val & 0xff;
				if ((val & 0x200) != 0)
					op.e_o_s = 0x200;
				bytes += size;
			}

			op.packetno = packetno;
			op.granulepos = granule_vals[ptr];
			op.bytes = bytes;

			body_returned += bytes;

			lacing_returned = ptr + 1;
		}
		packetno++;
		return (1);
	}

	// add the incoming page to the stream state; we decompose the page
	// into packet segments here as well.

	public int pagein(Page og) {
		byte[] header_base = og.header_base;
		int header = og.header;
		byte[] body_base = og.body_base;
		int body = og.body;
		int bodysize = og.body_len;
		int segptr = 0;

		int version = og.version();
		int continued = og.continued();
		int bos = og.bos();
		int eos = og.eos();
		long granulepos = og.granulepos();
		int _serialno = og.serialno();
		int _pageno = og.pageno();
		int segments = header_base[header + 26] & 0xff;

		// clean up 'returned data'
		{
			int lr = lacing_returned;
			int br = body_returned;

			// body data
			if (br != 0) {
				body_fill -= br;
				if (body_fill != 0) {
					System.arraycopy(body_data, br, body_data, 0, body_fill);
				}
				body_returned = 0;
			}

			if (lr != 0) {
				// segment table
				if ((lacing_fill - lr) != 0) {
					System.arraycopy(lacing_vals, lr, lacing_vals, 0, lacing_fill - lr);
					System.arraycopy(granule_vals, lr, granule_vals, 0, lacing_fill - lr);
				}
				lacing_fill -= lr;
				lacing_packet -= lr;
				lacing_returned = 0;
			}
		}

		// check the serial number
		if (_serialno != serialno)
			return (-1);
		if (version > 0)
			return (-1);

		lacing_expand(segments + 1);

		// are we in sequence?
		if (_pageno != pageno) {
			int i;

			// unroll previous partial packet (if any)
			for (i = lacing_packet; i < lacing_fill; i++) {
				body_fill -= lacing_vals[i] & 0xff;
				// System.out.println("??");
			}
			lacing_fill = lacing_packet;

			// make a note of dropped data in segment table
			if (pageno != -1) {
				lacing_vals[lacing_fill++] = 0x400;
				lacing_packet++;
			}

			// are we a 'continued packet' page? If so, we'll need to skip
			// some segments
			if (continued != 0) {
				bos = 0;
				for (; segptr < segments; segptr++) {
					int val = (header_base[header + 27 + segptr] & 0xff);
					body += val;
					bodysize -= val;
					if (val < 255) {
						segptr++;
						break;
					}
				}
			}
		}

		if (bodysize != 0) {
			body_expand(bodysize);
			System.arraycopy(body_base, body, body_data, body_fill, bodysize);
			body_fill += bodysize;
		}

		{
			int saved = -1;
			while (segptr < segments) {
				int val = (header_base[header + 27 + segptr] & 0xff);
				lacing_vals[lacing_fill] = val;
				granule_vals[lacing_fill] = -1;

				if (bos != 0) {
					lacing_vals[lacing_fill] |= 0x100;
					bos = 0;
				}

				if (val < 255)
					saved = lacing_fill;

				lacing_fill++;
				segptr++;

				if (val < 255)
					lacing_packet = lacing_fill;
			}

			/* set the granulepos on the last pcmval of the last full packet */
			if (saved != -1) {
				granule_vals[saved] = granulepos;
			}
		}

		if (eos != 0) {
			e_o_s = 1;
			if (lacing_fill > 0)
				lacing_vals[lacing_fill - 1] |= 0x200;
		}

		pageno = _pageno + 1;
		return (0);
	}

	/**
	 * This will flush remaining packets into a page (returning nonzero), even if there is not enough data to trigger a flush normally (undersized page). If there are no packets or partial packets to
	 * flush, ogg_stream_flush returns 0. Note that ogg_stream_flush will try to flush a normal sized page like ogg_stream_pageout; a call to ogg_stream_flush does not gurantee that all packets have
	 * flushed. Only a return value of 0 from ogg_stream_flush indicates all packet data is flushed into pages.
	 * 
	 * ogg_stream_page will flush the last page in a stream even if it's undersized; you almost certainly want to use ogg_stream_pageout (and *not* ogg_stream_flush) unless you need to flush an
	 * undersized page in the middle of a stream for some reason.
	 */

	public int flush(Page og) {

		int i;
		int vals = 0;
		int maxvals = (lacing_fill > 255 ? 255 : lacing_fill);
		int bytes = 0;
		int acc = 0;
		long granule_pos = granule_vals[0];

		if (maxvals == 0)
			return (0);

		/* construct a page */
		/* decide how many segments to include */

		/*
		 * If this is the initial header case, the first page must only include the initial header packet
		 */
		if (b_o_s == 0) { /* 'initial header page' case */
			granule_pos = 0;
			for (vals = 0; vals < maxvals; vals++) {
				if ((lacing_vals[vals] & 0x0ff) < 255) {
					vals++;
					break;
				}
			}
		} else {
			for (vals = 0; vals < maxvals; vals++) {
				if (acc > 4096)
					break;
				acc += (lacing_vals[vals] & 0x0ff);
				granule_pos = granule_vals[vals];
			}
		}

		/* construct the header in temp storage */
		System.arraycopy("OggS".getBytes(), 0, header, 0, 4);

		/* stream structure version */
		header[4] = 0x00;

		/* continued packet flag? */
		header[5] = 0x00;
		if ((lacing_vals[0] & 0x100) == 0)
			header[5] |= 0x01;
		/* first page flag? */
		if (b_o_s == 0)
			header[5] |= 0x02;
		/* last page flag? */
		if (e_o_s != 0 && lacing_fill == vals)
			header[5] |= 0x04;
		b_o_s = 1;

		/* 64 bits of PCM position */
		for (i = 6; i < 14; i++) {
			header[i] = (byte) granule_pos;
			granule_pos >>>= 8;
		}

		/* 32 bits of stream serial number */
		{
			int _serialno = serialno;
			for (i = 14; i < 18; i++) {
				header[i] = (byte) _serialno;
				_serialno >>>= 8;
			}
		}

		/*
		 * 32 bits of page counter (we have both counter and page header because this val can roll over)
		 */
		if (pageno == -1)
			pageno = 0; /*
						 * because someone called stream_reset; this would be a strange thing to do in an encode stream, but it has plausible uses
						 */
		{
			int _pageno = pageno++;
			for (i = 18; i < 22; i++) {
				header[i] = (byte) _pageno;
				_pageno >>>= 8;
			}
		}

		/* zero for computation; filled in later */
		header[22] = 0;
		header[23] = 0;
		header[24] = 0;
		header[25] = 0;

		/* segment table */
		header[26] = (byte) vals;
		for (i = 0; i < vals; i++) {
			header[i + 27] = (byte) lacing_vals[i];
			bytes += (header[i + 27] & 0xff);
		}

		/* set pointers in the ogg_page struct */
		og.header_base = header;
		og.header = 0;
		og.header_len = header_fill = vals + 27;
		og.body_base = body_data;
		og.body = body_returned;
		og.body_len = bytes;

		/* advance the lacing data and set the body_returned pointer */

		lacing_fill -= vals;
		System.arraycopy(lacing_vals, vals, lacing_vals, 0, lacing_fill * 4);
		System.arraycopy(granule_vals, vals, granule_vals, 0, lacing_fill * 8);
		body_returned += bytes;

		/* calculate the checksum */

		og.checksum();

		/* done */
		return (1);
	}

	/*
	 * This constructs pages from buffered packet segments. The pointers returned are to static buffers; do not free. The returned buffers are good only until the next call (using the same
	 * ogg_stream_state)
	 */
	public int pageout(Page og) {
		if ((e_o_s != 0 && lacing_fill != 0) || /* 'were done, now flush' case */
				body_fill - body_returned > 4096 || /* 'page nominal size' case */
				lacing_fill >= 255 || /* 'segment table full' case */
				(lacing_fill != 0 && b_o_s == 0)) { /* 'initial header page' case */
			return flush(og);
		}
		return 0;
	}

	public int eof() {
		return e_o_s;
	}

	public int reset() {
		body_fill = 0;
		body_returned = 0;

		lacing_fill = 0;
		lacing_packet = 0;
		lacing_returned = 0;

		header_fill = 0;

		e_o_s = 0;
		b_o_s = 0;
		pageno = -1;
		packetno = 0;
		granulepos = 0;
		return (0);
	}
}
